Question

Maribel is helping the art club build backgrounds for an upcoming play. They are painting arches onto wooden planks for the stage scenery. The shape of the arches can be found by the equation y=−x^2 +2x+8
. How tall must each arch be?(1 point)

7 feet

8 feet

9 feet

10 feet

Answer 1

Find the vertex (maximum) of y = −x^2 + 2x + 8.
x-coordinate = −b/(2a) = −2/(2·(−1)) = 1.
y(1) = −1 + 2 + 8 = 9.

Answer: 9 feet.